From CIC website (this site says I can't post links, so google it if needed)
Performing artists
Foreign artists and their essential support staff, the people that are integral to the performance, can work in Canada without a permit only under these conditions:
* They are only performing here for a limited period of time.
* They will not be performing in a bar or restaurant. If they will be performing in a bar or restaurant, performers and their staff each need a work permit.
* They are not entering into an employment relationship with the Canadian group that has contracted for their services.
* They are not performing for the production of a movie, television or radio broadcast.
Examples of performing artists who can come to Canada without a work permit:
* Foreign-based band or theatre group and their essential crew not performing in a bar or restaurant
* street performers (buskers), DJs
* a foreign or traveling circus
* guest artists within a Canadian performance group for a time-limited engagement
* World Wrestling Entertainment wrestlers (& similar groups)
* persons performing at a private event, such as a wedding
* air show performers,
* rodeo contestants
* artists attending or working at a showcase
* film producers (business visitors)
* film and recording studio users (limited to small groups renting studios not entering the labour market), (business visitors)
* persons doing guest spots on Canadian TV and radio broadcasts (guest speakers)