For all the hype about Teletubbies, the hottest kids' show on TV right now is actually Blue's Clues (Nickelodeon, weekdays, 9:30-10 a.m.), which recently surpassed both Sesame Street and Barney & Friends as the top-rated program among children ages 2 to 5. The reason for Clues' success is simple: It's one of the most engaging and imaginative series for any age group.

Much of the credit belongs to star/creative consultant Steve Burns. Along with his animated pet dog, Blue, Burns helps young viewers solve puzzles based on hints he finds around his Pee-wee-esque playhouse. (Sample brainteaser: What is Tickety-Tock the Alarm Clock's favorite nursery rhyme? The clues: the number 1, a grandfather clock, and a mouse. That's right, kids--it's "Hickory Dickory Dock"!)

Burns brings an infectious energy to the two-year-old program without creeping over into cutesiness. What's the secret to his perkiness? "I've developed an entire acting technique based on seven cups of coffee," he quips. "It's tough to be that ridiculously happy at 8 o'clock in the morning."

A voice-over artist who's done spots for the McDonald's Arch Deluxe and MCI's 1-800-COLLECT, the 24-year-old actor landed the Clues gig after a 1995 audition. The show's immediate success took him by surprise. "[I thought] 'Am I really the host of a children's TV show?'" he says. "Now I think it's great. It's a privilege to be loved by so many cool little kids. Sometimes I feel like Grover."

In fact, Burns says he identified with that Muppet growing up in Boyertown, Pa. "Grover was my childhood hero--he was a nerd," he explains, adding joshingly, "I often think, 'What would Grover do?'" He also gives props to yet another kids-show predecessor: "Mister Rogers is the guru of all time. I'm like the young, hyper version of him."

Still, Burns doesn't want to get pigeonholed as a children's-TV star. He recently turned in a powerful guest performance on NBC's Homicide: Life on the Street as a high school geek who murders a bullying basketballer. "No one on the show knew [who I was]--it wasn't, 'Let's hire the guy from Blue's Clues to kill this guy,'" he recalls. "But as soon as one person figured it out, it was crazy. I had to sign a lot of pictures." But Burns says he wasn't concerned about frightening his young fans: "I figured there weren't too many 4-year-olds up at 10 o'clock on Friday."

Besides, he says, kids don't recognize him without his trademark green rugby shirt (specially designed not to interfere with the show's blue- screen technology) and blue cartoon dog. In one example of how the show seeks to subvert stereotypes, Blue is a girl, despite her traditionally male color. And, Burns jokes, she can be a real...B-I-T-C-H: "She gets mad because I do all the interviews, but she did get credit in the title."

Burns will keep working with Blue for at least one more year. A Blue's Birthday prime-time special (with guests Rosie O'Donnell and Gloria Estefan) will air on Nickelodeon June 14 at 8 p.m., a Blue's Clues CD-ROM will be in stores this fall, and there's talk of a Clues movie. And even if Burns should leave, the show could go on without him: "I'm actually Blue's sidekick," he says. "She's way smarter than me."