Here's Louis CK's take on topical jokes (Boston Comedy via Sandpaper Suit):
"I just don't do that. It has a shelf life, and… I don't care about current events. They're hit so hard by comedians. That whole thing of, 'Hey, what the hell…' you know, 'And the eight babies lady…' You know, Jesus. And fucking enough. It's the most boring part of our national conversation, is the five headlines. You can't tell the news from Entertainment Tonight anymore. It's just a bummer. And I think it's one of the most boring aspects of stand-up, and it's just me being really harsh, is just the feeding on that shit. And taking the, 'Here's my take on it.' Oh, okay, that's about three degrees different from what Conan said, and Leno said, and Letterman said, and Jon Stewart, and Dennis Miller, and Spike Feresten, and Jimmy Kimmel, and Jimmy Fallon. And the columnist, and the Onion. And a bunch of bloggers...Your take on the Octomom, you somehow found a little territory in there that was just yours. And I really wish you had thought about something about yourself instead."
Now here's MY TAKE:
I don't know if you've noticed but the past few days I've been writing topical jokes. Why on earth would I do this? Two reasons:
a) As a joke-writing exercise
b) It's amazing practice for television writing
The truth is, there is ZERO money in alternative comedy. You either make money as an actor or a writer. I don't have a Johnny Hollywood Good Time Charlie face, so I may as well hone my writing chops.
That said, I would stay away from telling topical jokes onstage. Stand-up, more than any other form of comedy, is about honing and sharpening the same material. Granted, I don't feel you need to tell the same five jokes at EVERY show (I just realized this recently, so apologies to my fellow comedy colleagues) but it really is hard to let go of jokes that have the shelf life of one loopy afternoon at work.
Topical jokes: great for blogs/Twitter, but a waste of time onstage.