Depends on how you want to trigger them. From within the database themselves you have to use Agent. You could also just use the windows scheduler that will run a batch file on a specified time which connects to the database and executes the stored procedure using SQLCMD.exe
At my work I used Coldfusion server to schedule a Coldfusion page to run at some interval. That CF page had code to run a stored procedure... Pretty fast so I didn't have to wait for the database guys to schedule a job in SQL server (which took days)...