Anyone with a copy of the new DMG and MM can play along.
How It Works: Take the first letter of the last word in the post above you (not counting signatures). Translate that letter into a number; A=1, B=2, C=3, D=4; etc. That's the level of your encounter.
Now, take the last letter of the last word in the post above you (again, not counting sigs). This determines the scenario of the encounter, per the following chart:
A,B,C,D,E :: Battlefield Control
F,G,H,I,J :: Commander and Troops
K,L,M,N,O :: Dragon's Den
P,Q,R,S,T :: Double Line
U,V,W,X,Y,Z :: Wolf Pack
So you've got an encounter level and a scenario. Pick some monsters from the MM and design an encounter!
Don't forget to include some flavor text and tactical advice at the end.
What follows is numerous examples as people play along from home.