Yes, it is doable with changing background color for special occassion, like Happy Holidays or Mother/Father Day or Halloween or Sub_10. Universial celebrations only, please. And that's means no Independence Day or religion-specific holiday.
Maybe just leave it at New Year's, Mat's Birthday, the founding of the forum, and some other community related stuff. Let's have our own little holidays
Anyway, your call, AK. I'd love to see occasional background changes.