I think you're talking about a different variety of side project than I am. I'm more looking at short little explorations of CSS/JS/design to (1) teach myself new skills, (2) have a little fun, and (3) maybe get some "internet points" (that can hopefully be redeemed for job hunting benefits in the future). The question is whether the "internet points" (exposure) for silly projects would actually be useful, or possibly even detrimental to finding a job.
As far as freelancing goes, its going to be harder to get extra income with anything but your real name. There might be a way, but it probably has some dubious tax implications (although maybe you could search with a pseudonym and give your real name once hired).