Few things are more annoying than having to stop in the middle of a painting project, with a mess on your roller and a pan full of paint. To keep the paint and tools from drying out, wrap them tightly in several layers of plastic wrap, then stash it all in the refrigerator overnight. The paint will stay fresh, and you will be ready to resume work in the morning.
Related: Paint Like a Pro—8 Clever New Tools Under $10