A good trick is to invest in some low-caost, high-time hobbies. Most cities are surrounded by countryside so if you live near there, going out walking doesn't cost much. Rediscovering your love of books is also pretty thrifty as your local thrift store/charity shop is normally stocked to the gills.

Videogames can be a cheap hobby if you buy the last-last gen machines (PS3/Xbox 360) as they games cost a pittance and still look good on your HDTV.