As the masterminds behind gems like Stefon and What Up With That?, Bill Hader and Kenan Thompson have elicited a lot of laughs on Saturday Night Live. So, on the eve of Hader's big return as host this weekend, we wanted to know: Which of the iconic show's cast members have made them laugh?

From all things Phil Hartman to a lead-footed feline, here are the four sketches Hader and Thompson shared with Yahoo TV…

1. Jackie Rogers Jr.'s $100,000 Jackpot Wad With Martin Short, Christopher Guest, and Billy Crystal: "Billy Crystal was Sammy David Jr., Christopher Guest was this weird Indian detective, and they were doing Pyramid," Hader said of the 1985 bit, adding, "It's one of the funniest sketches ever."

[Related: Bill Hader Talks Hosting 'SNL' and Reveals the 1 Sketch He's Never Been Able to Do]

2. Toonces the Driving Cat: He drives around, all over the town, and he's one of Kenan's all-time faves. "I'm going to go with Toonces — any Toonces used to make me laugh a lot," Kenan said with a smile as Hader did a wide-mouth impression of the seemingly indestructible feline, which first appeared on the show in 1989. "And then the footage. I used to wait for that footage all the time — going over the cliff — [always the] same footage."

3. Phil Hartman as Frank Sinatra: Hader was quick to suggest the late Hartman, who was on the show from 1985 to 1996, singling out his impression of Old Blue Eyes during The Sinatra Group sketch. "He would make fun of Sinéad O'Connor," Hader said, cracking himself up at the memory. "He's like, 'Uncle Fester, what do you think?'"

4. Hartman as Unfrozen Caveman Lawyer: Kenan also had a Hartman sketch on his short list: the Neanderthal who survived the Ice Age by being frozen and thawed out in 1988. "That's my all-time favorite sketch," Hader said after hearing Kenan's pick. "I used to do Caveman Lawyer in my science class… Phil Hartman was amazing. He's kind of my favorite."

That made Kenan rethink their entire list, noting, "We could probably make all of them Phil Hartman ones."

Check out our video, above, to see the funnymen list their picks — and do their own Unfrozen Caveman and Toonces impressions — during our set visit earlier this week. And tune into SNL this Saturday at 11:30 p.m. on NBC to see Hader back as host of the show.