What does this character mean

[Minty]

囍 means 'double happiness' - it's a character usually displayed at weddings. You can find such a character displayed in big, gold writing with a red backdrop in luxury Chinese restaurants where small-scale weddings occur.

Yep, this is exactly what it means. Some times the writings are in red not necessarily gold. I would say red is more common than gold because it represents prosperity in Chinese culture.