Recs.
Updated
Philips Hue is an entire range of smart lighting products. Individual bulbs are $14.95, or you can get them in kits with different accessories (dimmers, or the bridge which acts as the heart of your home smart lighting).
Specs
Pros
Pro Tons of utility and customization
Philips has released the Hue API, allowing individual developers to create their own apps that utilize the Hue bulbs. These apps are often more robust than Philips' own app, letting lights change color in sync with music, flickering whenever you get a tweet, or can change colors to reflect the stock market. The possibilities are nearly endless.
Cons
Con Bulbs aren't super bright
The first gen bulbs (what are available right now) have a maximum brightness of 600 lumens - similar brightness to a 50-watt bulb. The second gen bulbs will have an increase to 800 lumens, which is in-line with the amount of light that 60-watt bulbs produces - however these aren't available quite yet.