All Things Britney

In case you have missed the 8,000 promos for it, tonight is the guest appearance from Britney Spears on "How I Met Your Mother." (CBS, 8:30 p.m.)

It's a double-edged sword for me. On the one hand, HIMYM is always one of those bubble shows, and anything that helps improve the ratings for what I consider to be the best sitcom on the air right now is a good thing.

But, geez, do I hate stunt casting at the best of times, and to do it with the world's most over-exposed (in many different ways) schizophrenic is not really the direction I want to see HIMYM go.

At least in the snippets they are showing as promos, Brit seems to be mostly sane-looking. And in a side note, they are auctioning off her wardrobe from the episode for charity. You have to wonder who would bid on it.

All of the rest of the CBS sitcoms - "Big Bang Theory," "Two & A Half Men" and "Old Christine" - are also new, though Spears-less. "CSI: Miami" (CBS, 10 p.m.) joins them with its first new episode since the strike.

MONDAY'S BEST BETS: "Canterbury's Law" (Fox, 8 p.m.) is following the "Rescue Me" format of mixing individual cases with a season-long arc, not really a surprise since both shows are produced by Denis Leary and Jim Serpico. It's followed by a new "New Amsterdam," which has surprised me by already getting the two main characters together in a romance just four episodes in.

ABC airs its monster reality lineup of "Dancing With the Stars" (ABC, 8 p.m.), followed by "The Bachelor" at 10 p.m. That runs against a new "Medium" (NBC, 10 p.m.)

The second season of "Greek" (ABC Family, 8 p.m.) kicks off tonight.

Finally, PBS' "Frontline" examines the Iraq war, beginning at 9 p.m.