Will & Grace
On Will & Grace, Alec Baldwin appeared as the character of Malcolm. Malcolm hires Will to work for his charity, but Will soon finds out that Malcolm is actually a secret government agent protecting the identity of Karen's dead husband Stanley, who is actually alive. Malcolm appeared in the last few episodes of Season 7 and the first few of Season 8. Here is a clip from the Season 8 live premier episode:
Friends
Alec Baldwin appears in two back-to-back episodes of Friends as Parker, Phoebe's overly positive and very enthusiastic boyfriend. In his first episode, he appears very briefly at the end of the episode, when he first meets Phoebe. But it is in the next episode, The One with Massapequa, where he truly shines. Unfortunately, it is very hard to find a clip from Friends on the internet (unless you want one that is either not in English or very bad quality) so this brief clip of the episode is the best I could find. I encourage you to go out and watch the whole episode, because he's really quite funny throughout the episode.
Saturday Night Live
Alec Baldwin has hosted SNL a total of 14 times, second only to Steve Martin who hosted 15 times (be sure to watch the Academy Awards next Sunday, March 7 when the two of them co-host together). It's hard to pick just one clip from all of Alec's SNL appearances, but I chose "The Tony Bennett Show" because Baldwin's Tony Bennett impression is just amazing. And in this particular clip, the real Tony Bennett pops in and the two Tony Bennetts sing together. Enjoy!