CS

.....project ideas?

Requirements:

[list]
Something useful that can be later sold. Games are allowed but discouraged
Something that shows a lot of OOp implementation
Something hard to program. (I'm the best in class. I need to win the honors)
[/list]

I was originally going to do a OCR reader for hard written documents. Upon finishing the first research session I was aware the project had too high a chance of failure and too small a time frame to be completed successfully. I downgraded it to a simple captcha reader but again it was probably bound to fail.
I am now stuck without any ideas.

Can please /prog/ provide some ideas?

A program which extracts youtube download urls from pages and downloads HD clisp to user specified directory with full titles.
A stable and fast SecondLife clone.
An alternative to Shiichan and/or 4chan which trumps both in features and speed.