I saw someone at work using this today, and thought this would be perfect for post-surgery! Water bottle that syncs with your phone and has a light up feature for remind you to drink. It's a little steep for me at $55, but thought I would share.

http://hidratespark.com/products/teal

I bought one! I like it, and it lets you add other liquids, manually, by ounces, so you can tell it you had 16 oz of juice or whatever other liquids you're having. One of the things I do not like is that you can only have pure water in the bottle. If you add any flavorings like powder or lemon, it might affect the sensor. I can't stand plain water these days, so I tend to use the feature that I can add my other liquids and just drink one full bottle of plain water.

Yeah, it looked like calibrating the sensor might be a pain too.