If you missed the first StarCraft or its Brood War expansion, you have a new chance to play them. A new fan mod for StarCraft 2 includes remade versions of all six campaigns from the SC1 era.
StarCraft: Mass Recall uses all the original units and tech trees. The dialogue, briefing screens and voiceover are all intact as well. You can watch the original cutscenes or new in-game cutscenes built by the modders. The campaigns, playable with three difficulty levels, include some maps that weren't used in the retail versions of SC1 and Brood War:
Mass Recall contains 68 maps, 59 from the original Brood War game, 3 that were hidden or deleted on various Starcraft supports, and 6 from the 1998 demo campaign.
The visuals are obviously a lot sharper as well. Here's some footage from two of the missions in Mass Recall:
You can download Mass Recall for free at SC2Mapster. You'll need to own StarCraft 2 and expansion Heart of the Swarm to play it. Also, installation takes a little bit of effort because you're not just grabbing it through Arcade.
If you haven't played SC1 or Brood War, I'd strongly recommend checking out these old campaigns. While certain missions might feel a bit dated, they're definitely worth playing. The story for SC1 sets ups a lot of crucial elements in SC2's narrative as well, such as the rise of Kerrigan and her relationship with Raynor.
StarCraft 2's saga will be completed next month by the release of second expansion pack Legacy of the Void. Void's campaign puts players in the shoes of Artanis, the Protoss leader looking to retake the race's homeworld of Aiur. He and his armada will also need to confront a threat trying to take over the whole galaxy.
If you're looking for more free entertainment before Legacy of the Void's launch, download Whispers of Oblivion. These three free missions are a prologue to the expansion's plot. You can download them even if you've got a free SC2 starter edition.