Today and today onlyThis week (as we've now learned from JGonzo of Capcom), Xbox LIVE Gold members can log on to the Xbox LIVE Marketplace and download the most recent of the Classic series, Mega Man 10, for 400 Microsoft Points, or five dollars (depending on how you look at it). That's half the normal 800 point/ten dollar price.
This comes as a part of Microsoft's "Spring Leftovers" sale, which also includes After Burner Climax for the same price, and Scrap Metal for 800 points.
For the Blue Bomber's latest, this is a hard deal to ignore. Plus, it helps take the sting out of the cost of the extra downloadable content (including the playable Bass and the Mega Man Killer stages) when you're not paying full price for the game itself.