This is an extremely useful site, and it has one of the best lookup interfaces of any FEC data site I've seen. I would give it 5 stars in an instant, but it is down somewhat frequently.
Celebrities and Politics - I generally decry the influence of celebrities on politics. But I have to admit, this site is a hoot. It has a searchable database of past political donations of celebrities. For example, you can look up how much Jessica Alba, Jennifer Aniston or Kevin Bacon have donated to campaigns in the past, and which candidates they've supported. It's all public information, collected in a convenient place.
In addition, you can search under headings for Billionaires (see how much the Wal-Mart family has given), Sports Stars (Andre Agassi gave over $130,000 to Democrats), Media (Anderson Cooper, Ben Stein and Hugh Hefner), Business Executives (Jerry Yang's all over the place - I don't know where he stands), and Politicians themselves.
If you want a broader searchable database (e.g., to see what your neighbors, friends and bosses have donated in the past), this Fundrace site is great too:
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