Command & Conquer Remastered Collection just came out last week. If you want to relive the real-time strategy action, you can find the game on sale for $17.99 via Green Man Gaming.
This deal is for the Origin version of the game. A free Origin account is required to redeem the key. You also need 32GB of free space on your hard drive.
The collection is comprised of Command & Conquer: Tiberian Dawn, Command & Conquer: Red Alert. It also includes their three expansion packs: Covert Ops, Counterstrike, and The Aftermath.