Ask Tim Allen to describe his character on "Home Improvement" - the host of a home fix-up show - and he'll make the obvious comparison.

"I went to a public service television station. We started this tool show like Bob Vila's `This Old House.' It got so popular that I turn it into this man's stupid Robert Bly show - round-table discussions with carpenters about what bothers you. A sort of men's show," Allen said.And it had to happen. Vila, the man who was an inspiration of sorts for "Home Improvement," appears on the show tonight (7:30 p.m., Ch. 4).

(Of course, Vila is no longer with "This Old House" - he now hosts the syndicated "Home Again.")

Just look for a little clash of egos. Or, at least, a bit of envy on the part of Tim as he tries to outdo his idol.

TOOL TIME: Although Allen doesn't claim to be a handyman - he's not Bob Vila - he does have an affinity for power tools and tinkering.

"Once the series got bought, I went and bought a chipper/shredder, where you take yard waste and make it useful mulch for around bushes," Allen said. "That was a $900 purchase. Rather than just buy champagne and say, `Yoo-hoo,' I bought that.

"But I rewired my wife's vacuum cleaner. Honest, I put a larger amp motor, with a full bearing shaft up in top, that will suck the rear end out of a cat, and I'm not kidding. . . . I did that one thing in my life, and it really made her life a lot easier, because it vacuums better."- TONIGHT ON THE TUBE: There's a monkey in the Full House (7 p.m., Ch. 4); Nova (7 p.m., Ch. 7) explains the sense of smell; a teen claims to have shot a friend to death accidentally on Law & Order (8 p.m., Ch. 2); Roseanne (8 p.m., Ch. 4) considers breast-reduction surgery; Frontline (8 p.m., Ch. 7) profiles Fidel Castro; Kelly runs into her ex-husband on Coach (8:30 p.m., Ch. 4); and Roseanne and Tom Arnold, Bill Cosby, Howie Mandel and Burt Reynolds are Class Clowns (9 p.m., Ch. 4).

- LOOKING TOWARD WEDNESDAY: Kevin feels smothered by his new girlfriend on The Wonder Years (7:30 p.m., Ch. 4); there are hourlong episodes of Seinfeld (8 p.m., Ch. 2) and Night Court (9 p.m., Ch. 2); Anything But Love (8:30 p.m., Ch. 4) airs its final episode; and one couple fights over custody of a dog while another battles for custody of a child on Civil Wars (9 p.m., Ch. 2).

- THE WINTER OLYMPICS: Coverage continues tonight on CBS (7 p.m.-10 p.m., Ch. 5), featuring the finals in pairs skating and alpine skiing, and a highlights show at 10:35 p.m. (Ch. 5). Tomorrow, you can tune in from 6 a.m.-8 a.m. (Ch. 5), 11 a.m.-4 p.m. (TNT) and 7 p.m. 10 p.m. (Ch. 5) with highlights shows at 12:40 p.m. (Ch. 5) and 10:35 p.m. (Ch. 5).