This is arkatipe's watering spout (rose), with eagleapex's bottle threads thingiverse.com/thing:10489 subtracted from it.

I'm leaving for my honeymoon in a couple of weeks, so I needed a way to keep my plants alive between the times when the neighbor will stop in to water everything. So I made this watering spike.

My bit of testing showed that it took about 12 hours on average for the water in the 2L bottle to drain. It lasts a little longer if the ground is wet to begin with.

EDIT 7/26/11: Spike with Threads added. This one also includes 3 "fill layers" in the middle of the spike, which makes a sort of filter at 90% fill. It slows down the drainage a little bit, and keeps particles from being sucked up into the bottle.

This is a watering spout for a 2L bottle.

I originally designed this so that a bottle cap could be press fit onto the sprinkler once it was done printing. However (at least on my printer) the plastic came out a little bit too small. This meant that I could screw it onto the bottle without the addition of a hollowed out bottle cap.

But if yours prints the right size then you'll probably have to do this. You'll just need to drill a hole in a bottle cap and press it into the sprinkler head. The addition of hot water would make this easier.

My thoughts behind this were mostly recycling - oriented. If you're saving the bottle, you might as well save the bottle cap, too, and this way you know you have something with a water tight cap (though this isn't important as leaking is kind of the point)

Also, I know this uses more plastic than is necessary. But that's kind of the point of a 3D printer. This technology lets us make things that aren't cheap pieces of crap. So enjoy the 1/8"-thick walls on a piece of plastic. You can't get that in the store.

Edit: Check out thingiverse.com/thing:10600 for ljudmila's version with threads.

My wife wanted a skinny pot and we also need a new orchid pot, so I modified hathawsh's design to be parametric.
This is a work in progress because I haven't actually printed it so I don't know how it will work.

This is a plug designed to go in the upper holes of NFT and similar hydroponics runs. It is not entirely waterproof, but will help stop rain entering your system and diluting the nutrient. More importantly, it cuts out the sunlight and prevents algal scum growing in the run immediately beneath an empty hole.

Oh, and it keeps frogs out.

A little 190ml watering can for watering your houseplant / deskplant.
I haven't yet made or modelled this as I don't have a makerbot. yet.

UPDATE: On closer inspection, I shortened the length so that it can fit in the makerbot build space. A slightly less pleasing capacity of 190ml (was 200!).

Have added a couple of feet on the back edge so that it can hopefully be printed sitting on its back, longest side sitting vertically. These should be cut or grinded off once printed. Comments welcomed below.

This is the lid (blue part) for the aeroponic garden. Includes 6 holes for seed pods ( thingiverse.com/thing:695 ), a hole for the airline tubing, and a 1" hole for adding water. Cut out of 1/8 or 1/4 inch acrylic.

Details of my DIY aeroponics project can be found on kellbot.com