Basic 5x5 Fountain
This is nice for a courtyard, or maybe a castle garden, etc etc. You will need: 16 blocks of Cobblestone (you can use any solid block, but Cobblestone look the best.), 1 bucket of water and 2-3 blocks of Lapis Lazuli
How to make it:
1.) Make a 5x5 square outline with the Cobblestone blocks.
2.) Stack the Lapis Lazuli blocks in the exact middle of the square formed by the cobbles.
3.) Finally, use the water bucket on the top of the lapis blocks. The water should flow down the sides and fill the entire square without spilling over. If it didn't, tweak the Cobblestone blocks until it gets just right.
4.) Enjoy your fountain!