An informational site about graph paper. I don't exactly know the market but I'm sure it's big enough to warrant some investment into developing the site and then selling it off to a copy who makes graph paper. I would venture to say undeveloped probably reg fee or low $xx but developed PROPERLY maybe $10k or so. Who knows ... do enough work on it and the sky is the limit ... okay well maybe not unlimited potential but still this market is probably big enough to warrant a big enough pay off. :P
I like this suggestion. Faint lines or something that you can print out on computer paper to make it resemble graph paper. Different sized boxes, etc etc. Could be cool