Capablanca Chess (10×8, adding the Archbishop [bishop+knight] and Chancellor [rook+knight]) combined with Crazyhouse's hand-and-drop system. Capturing an enemy piece converts it to your own color and adds it to your hand. On your turn, instead of a normal move you may drop a piece from your hand onto any empty square (pawns may not be dropped on the 1st or 8th rank).
Simplifications: castling and en passant are omitted. Check and checkmate aren't enforced — capturing the king directly ends the game.