think it's safe to say that Sphinx's Revelation is still the defining card of Return to Ravnica Block Constructed. At a glance, it looked to me like straight white-blue was the most popular Sphinx's Revelation deck, but it's not hard to find someone playing white, blue, and any third color.
Sphinx's Revelation should win any game in which the opponent doesn't have it and gives the player who has it plenty of time to cast it, so Mono-Red aggro appears to be the dominant counter strategy, and that appears to be fairly successful.
There are also a handful of midrange decks that I assume exist to prey on the Red decks, but they generally also have some kind of plan for Sphinx's Revelation.
Anyway, the coolest deck I saw, skimming through some Magic Online Daily results was this Bant deck that used Gyre Sage to power up huge Sphinx's Revelations.
I think Gyre Sage is one of the more underappreciated cards in Standard right now, and this looks like a good way to use it. I like that this deck focuses on creatures over spells to have plenty of fuel to power Gyre Sage, and I love Trostani, Selesnya's Voice in a format where people are playing a lot of Mono-Red.
Part of me wants to see Stolen Identity in this deck so Trostani can populate all the best creatures, but I suspect that's unrealistically greedy. There's a chance it's strong enough to bother with in block though, right? The deck has fliers and detain to force them through. Someone, make this happen!
hacienda's Block Constructed Gyre Revelation
Block Constructed – 3–1, Magic Online Daily Event
Sam Black is a Platinum Pro Player and longtime writer for StarCityGames.com. He is a respected deck builder and took over Daily Decks for the first half of 2013. If you have an original deck you'd like to see featured, email him at firstname.lastname@example.org.