Hey EMC, this morning I was browsing through Twitter and noticed that our dear Dinnerbone has been making a few tweets in the last couple days of some stuff that has been added to the launcher (without you even noticing). Basically Mojang has been adding all of the official Minecraft releases to the launcher going all the way back to Minecraft Classic. You can check out the list HERE But you will have to open up the launcher to play these of course I know I might go and download the Beta 1.8 update since that is when I first started playing Minecraft and might find it nostalgic. *Be careful when opening Save files with older versions as they can potentially be destructive to your creations.
I'd recommend you to create a separate profile for early versions of Minecraft, in that way you can prevent yourself from loading the wrong save
I started WAYYYY back in alpha XD EDIT: This is when I started playing NOT what version I recently tried.