Well I haven't played since the halloween update but what I had done so far on my latest map was;
*An automatic train station(where you spawn) that goes to all the project I got on the map.
*A green house for, trees,cactus and whet.
*An Observatory from 10 levels below sea level and goes up to the sky limit(Plan to have it from bedrock but that will have to wait).
*A dock in a mountain(Yet to build anymore at this spot)
*And my latest(still unfinished project), a calculator that got a 3 x 5 redstone torch panel and that you can subtract and add numbers(still not done and only one digit panel so can't go below 0 or above 9)
... I really should get my calculator finished soon ._.