I know, I've been in a crazy baking mood. The problem is that I go online and see these yummy recipes and then I start craving the end product. That's how I ended up baking lemon bars for our movie night (2010: The Year We Make Contact).
So the key to good lemon bars is apparently the lemons. You should use freshly squeezed lemon juice and lemon zest. Lemon zest is from the outer skin of the lemon. You get it from using a lemon zester, or if you're a poor grad student like me, from using a grater and grating the outer skin. Make sure you don't get the inner white rind, it's very bitter, and zest the lemons before squeezing them.