Tonight on How I Met Your Mother, Ted's little sister comes to visit and, judging from the previews, needs to be kept away from an overly attentive Barney. (CBS, 8:30 PM)

You may not have heard, but there are "fall finales" now, where a show wraps up its fall batch of shows before taking a nice break until (at least) spring. Both Chuck and Heroes have fall finales on NBC tonight, and that means it will be a while before you see either one again. (NBC, 8 p.m. and 9 p.m.)

What's more of a finale than a "fall finale"? A complete finale, and tonight, NBC's Christian Slater flop, My Own Worst Enemy, says goodbye forever. (NBC, 10 p.m.)