This script allows you to check the several availability windows for the current day, and thus more surely program any maintenance windows without stopping SQL Agent jobs. Just paste into Query Analyzer and run. SQL 2005 variant.
Update: Now gets information about backups made outside SQL Server, like Veritas or IBM TDP. Optimized several parts of the calculations.
Edit: looks like some of the indentation i made in this online editor broke the script. All fixed now.