It's a big weekend for horse fans: The 138th running of the Kentucky Derby takes place on Saturday. For anyone who's not familiar with the race, a thoroughbred’s win in the Derby is almost always followed up by a run in the Preakness Stakes. If all goes well, it’s then on to the Belmont Stakes in search of the elusive Triple Crown of horse racing. (The last horse to win all three races was Affirmed in 1978, making for quite a drought.)

Once a horse's 3-year-old racing season is complete, most champions enter retirement and head into the breeding shed for new careers as stallions — with some exceptions, of course. Here’s a look at how the champs of the past five years are now spending their days.

Animal Kingdom

2011 Winner, Animal Kingdom: Rest, Rehab — and a Potential Comeback

After winning the Derby as a 21-1 longshot in 2011, Animal Kingdom remains a charismatic favorite in the hearts of fans as well as his owners, Team Valor. He notched a close second-place finish in the Preakness, but was then diagnosed with a string of injuries following the Belmont Stakes including one in March that has temporarily sidelined him.

The 4-year-old chestnut colt recently spent 30 days resting in Palm Meadows, Fla., which he's following up with another two months of R&R at Fair Hill Training Center in Elkton, Md. While all of this rest probably isn’t as exciting to Animal Kingdom as training and racing, he’s taking it well. "He understands, to some extent, that he's supposed to be resting," says Megan Jones, director of client relations for Team Valor.

It helps that Animal Kingdom has plenty of company during his recovery. According to Jones, his team of owners are frequent visitors, and depending on his mood, he’ll either be loving or playful — the latter typically ending in a game of grabbing. (Animal Kingdom believes that all belts and jackets belong to him, not the humans wearing them.) One of his favorite visitors is Dave Rock, an assistant trainer whom Jones says the horse would likely recognize 10 years from now.

Depending on how Animal Kingdom heals over the summer, Team Valor has to decide whether to retire him or put him back into training for the prestigious 2013 Dubai World Cup. In the meantime, he's ready to handle whatever comes next. As Jones puts it, “He knows when he can play and when it's game time.”

Big Brown

2008 Winner, Big Brown: The Studly Traveler

When he entered the 20th starting gate for the Kentucky Derby as the 2-1 favorite, Big Brown became the first horse ever to win from that far outside position. He then went on to win the Preakness Stakes, setting himself up as the first potential Triple Crown winner in 30 years.

In the days leading up to the Belmont, questions swirled about an injury to Big Brown's left front hoof, but he still went out as the favorite on race day. The Triple Crown trifecta wasn't meant to be: In a controversial move, jockey Kent Desormeaux slowed the horse in the homestretch on a gut feeling that something was wrong. Big Brown finished dead last — the only Triple Crown hopeful to carry that distinction. Two weeks later, a photo showed a dislodged shoe on his hind leg, which could have caused the oddness Desormeaux detected in his gait.

Big Brown continued his illustrious career, winning a tough-fought Haskell Invitational, followed by a win in the Monmouth Stakes in 2008. After suffering an injury while prepping for the Breeders' Cup, he was retired to stud at Three Chimneys in Kentucky. Life in stud certainly suits Big Brown: When he’s in the shed with the mares, “he’s definitely enthusiastic about his job,” says Jen Roytz, the farm's marketing director.

His easygoing nature allows Big Brown to also travel. He spends his summers in Australia for the Southern Hemisphere breeding season, where Roytz says that he’s extremely popular.

Of course, that’s not to say he isn’t beloved in Kentucky — fans from all over the country visit Three Chimneys to see Big Brown, who’s featured on daily tours of the farm. He’ll stand patiently for photos and videos, proving that the champ has settled into his new life as a living legend.

Mine That Bird

2009 Winner, Mine That Bird: New Mexico or Bust

When Mark Allen and Dr. Leonard Blach decided to buy a thoroughbred, they wanted a racehorse, not a stallion — and that’s exactly what they got in Mine That Bird, the plucky gelding from New Mexico who nabbed the 2009 Kentucky Derby as a 50-1 longshot with jockey Calvin Borel on board. The win shocked just about everyone at Churchill Downs because Bird was the biggest longshot in the history of the race — a $2 win bet paid $103.

Mine That Bird ran in the Preakness, finishing a length behind champion filly Rachel Alexandra. (In a bit of controversy, Borel was aboard Rachel, whom he rode to victory in the Kentucky Oaks.) At Belmont that year, Bird finished third. He went on to race seven more times without a win before being retired in November 2010.

As a gelding, “romantic” afternoons in the breeding shed simply weren’t in the cards for Mine That Bird. After spending much of his career in New Mexico, that’s where he headed for retirement to Double Eagle Ranch. In true form, he’s keeping busy — not only does he regularly visit the racetrack next door for a gallop to ward off boredom, but he’s also the subject of a book trilogy about his Derby exploits.

Mine That Bird also loves the attention of his adoring fans. “I think he knows that he’s a celebrity,” says Dr. Blach. As soon as he sees cars driving up to his fence for photos, he’ll pose for a treat. Tip: Peppermints are his favorites, but he won’t turn down carrots or apples.

Street Sense

2007 Winner, Street Sense: Busy Kicking Back With His Rivals

Ask anyone who follows horse racing, and they’ll likely tell you that the 2007 Triple Crown season was one of the most exciting in recent history.

The thoroughbred class of 2007 featured some of the strongest racehorses ever: Street Sense, Hard Spun and Curlin battled again and again for racing’s top honors.

When Street Sense won the 2007 Kentucky Derby, Hard Spun finished second. When Curlin won the 2007 Preakness, Street Sense took second, and Hard Spun came in third.

Street Sense went on to win the Travers Stakes, and he finished fourth in the Breeder’s Cup Classic, before retiring to stud for Darley America at Jonabell Farm in Kentucky. According to Charlie Boden, head of sales for Darley, “he’s a pro” when it comes to covering mares, which is why he also heads to Australia for the southern breeding season.

Believe it or not, Street Sense and Hard Spun continue to be rivals off the track, since both are now in stud at Jonabell. They're paddock neighbors, and every now and then, they’ll race the fence line against each other. When that happens, the handlers just shake their heads and say, “There they go again,” notes Boden. Street Sense has family at the farm, as well — his father, Street Cry, is just a few stalls away, making his retirement rich with family and old friends.

Super Saver

2010 Winner, Super Saver: A Proud Papa Retires in Kentucky

Leading up to Derby Day 2010, renowned horse trainer Todd Pletcher had prepped almost two dozen hopefuls for the race — without a winner. His latest charge, Super Saver, changed that, racing to victory in 2:04:45 over a muddy track. (Super Saver’s victory would also give jockey Calvin Borel back-to-back wins in the Derby, and his third win in four years.)

Super Saver, who was bred and raised by WinStar Farms in Kentucky, went on to compete in three additional races, but he never finished better than fourth place. Following those races, an exam showed the he had bruising in all four legs, so the colt was retired back to his familiar digs at WinStar Farms in October 2010.

“The final decision to retire Super Saver was a difficult one that may not be popular with fans but should be very popular with our breeders . . .. We felt like he had nothing more to prove,” WinStar vice president Elliott Walden told The Blood Horse.

Super Saver stood his first season as a stallion last year. His first foal, a filly, arrived in mid-January 2012. Soon after, WinStar shared a video of another newborn filly standing for the first time.

WinStar has great expectations on Saturday for colt Gemologist, who is undefeated in five races and is considered a top contender for this year’s Kentucky Derby. Gemologist’s sire, Tiznow, is just a few stalls down from Super Saver, so the barn will be buzzing with excitement.

The Kentucky Derby will take place Saturday, May 5, at Churchill Downs in Kentucky, and will be broadcast on NBC. Click here for full viewing details.