How about cooling down today with a free Slurpee from 7-Eleven? The convenience store giant turns 81 this year, and in honor of that, and the fact that today happens to be 7/11, anyone who wants one can pick up a 7.11 ounce Slurpee at participating stores until 11PM this evening. (They started, naturally, at 7 this morning.)So why are you still at your computer?......