I like Wikipedia to look stuff up quickly but you do have to know what you are looking at and take it with a grain of salt.
I had to do a presentation about the Olympics recently, for a Tae Kwon Do class, and found it useful, not so much for research but for a quick run through the history of it as each Summer/ Winter games had a page w/ anecdotes, etc. about it. I read a couple of books first so I had some ideas about things that I was interested in but, as a quick source of lots of info, it was very useful. The graphic represenatations of women's swimming medals were an interesting depiction of the power of modern chemistry (1968