Google Play crossed a rather significant milestone this morning: something to the tune of 25 billion app downloads. While the accomplishment is weighty enough on its own -- especially given that the store also offers books, music and movies, which aren't included in this tally -- Google is celebrating in symbolic style with a number of apps and games for sale at just $0.25 over the next five days. Among the mix of discounted titles, you'll find publishers such as Gameloft, Electronic Arts, Rovio, Runtastic and Full Fat. Not to stop there, shoppers will also discover a curated collection of 25