Pretty sure Christchurch is the perfect city for cycling… well at least in New Zealand. If your a keen (or even fun-having casual) cyclist, why not go for an overnight camp on your bike?
Gets some buddies together along with food, entertainment and shelter together on your bikes – I recommend panniers for carrying stuff, but even DIY efforts like a bucket on your handlebars or beer crate on the back will help. Typical overnight trips include the northern beaches (most are patrolled, so its fun to hide your tend in the sand dunes), sumner / taylors / banks peninsula or the inland lakes for the more adventerous and stronger cyclists.
Great way to get out in the open, have a few drinks and a laugh over the holidays.