Cheapskate alert: You can stop by 7-Eleven on Monday, 7/11/11, for a free Slurpee.

To celebrate their 84th year of existence and 7-Eleven Day, participating locations across Oregon will be dolling out free 7.11 ounce Slurpees (a little under a fourth the size of the colossal Big Gulp) all day. If you're looking to get a little more involved in the celebration, one special 7-Eleven (7170 Beaverton Highway) will host a series of birthday-themed activities, like timed Slurpee drinking contests and one-minute 7-Eleven themed challenges, from 11 am to 1:30 pm.

To whet your thirst for the semifreddo soda, here are some Slurpee facts courtesy of :

- The Slurpee was first invented in 1959 by the owner of a Kansas hamburger stand- The first Slurpee-freezing-machine was powered by an automobile air conditioning unit- Half of all Slurpee drinks sold are purchased between 4-11 pm - Summer means Slurpee time: more than 40% of all Slurpees are sold in June, July and August- Every year, 7-Eleven sells enough Slurpees to fill twelve Olympic sized swimming pools