To celebrate Sonic the Hedgehog's 19th birthday (the American release date of the first Genesis game was June 23, 1991), Sega of America is dropping prices on downloadable games and DLC, most of which is related to Sonic. Offers on each platform have a different start date and a different duration.

The PSN sales will be active today through Tuesday, July 6, and include the PSP Sonic Rivals games ($10.99 or $13.99 for 1 or 2, respectively, or $17.99 for both) and discounted DLC for Sonic & Sega All-Stars Racing, Sonic Unleashed and Sonic the Hedgehog.

iPhone sales run tomorrow through June 30, and include discounts on the iPhone's Genesis games (Streets of Rage and Golden Axe are at the magic 99-cent price at which they start to seem like a good idea) along with Super Monkey Ball ($2.99) and the iPad's Super Monkey Ball 2: Sakura Edition ($4.99).

Finally, the XBLA sale will begin -- and end -- Thursday, June 24. If you want to buy any of the Genesis Sonic games for $3 each, you'd best have your Microsoft Points ready that day.