I just looked at stocks that are mostly large-cap, and said "Is this stock over or unvalued" It's tough to tell, but just take a look at some stocks. Google I bought at ~290, and I think that that stock will go up to at least ~350 as the economy recovers. Others were things that may move soon (Ford, etc). I have a short term strategy as well (in terms of the 3 months of this game), which we'll see how it goes.
As far as the stocks tanking this week, I'm thinking I'm just going to sit on them. Everything I bought I think is undervalued (except for Ford), so I think I'll gain back whatever I lost over the next week or two.