There's several awesome games up for grabs right now for one day only, in the One Special Day Bundle which is being in help in support of SpecialEffect, a charity that makes gaming more accessable to those with disabilities.
The games included in the bundle include the excellent Dirt 4 and amazing WW2 shooter Tannenberg when you pay $10 or more. Also included in the base bundle is Broken Age, and Purrfect Date, a quirky cat-dating simulator.
For the $5.38 tier, there's also Bomber Crew, which is a strategy simulator with a surreal cartoon asthetic, and The Swords of Ditto: Mormo's Curse, a pretty decent aRPG, as well as Stronghold Crusader 2.
Even if you just pick up Broken Age, it's a great deal, but I really recommend Dirt 4, which is only a couple years old and a pretty awesome entry in the Dirt series. Tannenberg is also well worth the price of admission, being a pretty spectacular and under-rated WW2 shooter.
The new Humble Monthly Bundle is also available right now and includes COD:WWII and the Crash Bandicoot N. Sane Trilogy for a cut down price.