I'm a healthy, low-risk age, person in a stable work situation. I realize I could run critical errands or tasks for folks in need near me on an ad hoc basis at night or first thing in the morning. Are there any sites that exist or have been setup recently where I could find "gig" type tasks without committing to a fixed schedule?

I'm thinking of something like volunteer TaskRabbit cases to deliver groceries for someone elderly, or deliver supplies for a hospital, etc.