This is a really great resource if you're not sure what typeface to use for a project. It's called TypeConnection, the "typographic dating game". The reason why it's awesome is because it doesn't give you the answers immediately, you have to match them together. It gives you the history of each one, the mood, and compares their qualities (x-heights, serifs, ect). It tells you when you pick the right or wrong pair, but it also tells you why in detail.