Yeah, Joseph Gordon-Levitt. *hands* I don't know either. My celebrity crushes are usually very transient and more on the level of "Wow you're hot" (Eliza Dushku, for example) and/or "Wow, you're good in this particular thing I'm watching" (...pretty much everyone in Inception, actually) than "Wow, you're awesome and I must watch everything you've ever acted in." This kind of celebrity enthusiasm is something I associate with my mother, who had a years-long obsession with Colin Firth that resulted in me seeing pretty much everything Firth had acted in up to the late 90s, whether I had any personal interest in it or not. (Like the one where he's a theater owner in Argentina and ends up murdering his roommate. That film was just odd.)

Anyway! 3rd Rock is kind of a long time-investment, but I will probably get around to watching at least a few episodes sooner or later. :-) As for voice acting, I know JGL voiced the main character in Treasure Planet, but I'm not sure if he did anything else. I should check IMDB sometime.