If you want complete control of how your phone reacts to calls and text messages in nearly any situation, then a tool recently released to the Android Market called Call Master has your number. This is probably the most in-depth, advanced call and text firewall for Android, offering some insanely useful features. It's from the same developer as Root Call Blocker, and actually uses that as its base.
With Call Master, you can block calls and texts from a specific number after a certain time, send certain number straight to voicemail or auto-hang up on them, keep calls or texts private, and much more. The best part is that this app is completely automated, so you can set a schedule and never have to think about it again.
Want to ignore calls from your job on weekends? Don't want texts after 10 or 11 at night? Need to keep certain calls out of the call log? These are just a few examples of what you can do with Call Master.
Since the app is in open beta right now, it's free in the Android Market and is updated often. Hit the link below to download.