You've got a Thermarest or camping pad that sits in your closet or garage for 362 days out of the year. Let's put it to use more often! - Do ab exercises on it!
One of the reasons it is difficult to do ab exercises is that on a hard floor or even moderately cushioned carpeted floor your lower back is hurting from the ground pressure on it. If you are wearing a belt or the waist band on your pants is bulky it is worse. However if you've got a pad that you've kept handy in your family room discreetly hidden behind the couch then it's super easy and comfortable to bust out some abs while you are watching TV or in between Face Book and blogging posts.
I have been doing 100 abs a day for over 4 years now. Keeping a strong core is really fantastic for avoiding injury in any endeavor. so... Put your camping pads to use!