Red Envelope is known as lai see in cantonese or hongboa in mandarin. This is a monterary gift. The red colour of the envelope symbolises good luck and is supposed to ward off evil spirits. The designs of the red envelope has changed over time, gold and red envelopes are the most popular. The ones I'm giving out this year are gold...aren't they cute!
The amount of money contained in the envelope usually ends with an even digit as in chinese beliefs off number money gifts are traditionally associated with funerals.
So being married during Chinese New Year is quite costly as the red envelopes are typically given to the unmarried. So me and Sin won't be receiving any :-(, oh well.