After a quick four-day work-week, the weekend's here again. If you spent too much over the last three-day weekend, know that a night at the theater is probably out. So are wine-tastings and fund-raisers. But there are always local concerts, free art gallery openings and at least one food-centric street fair going on this weekend. So it's not all bad! Here are ten cheap things going on around St. Louis.Fairmount Park's Party at the ParkOK, I'll get this out there in the open. This Friday night ev