Floor exercises fall into the category of Keep-It-Simple-Stupid exercises. Basically, every muscle you choose to work can be worked on the floor of your den, living room, bedroom or some other area in your home. What you do not get from at home floor exercises that you can get at the health club is conversation and social time, so this should be taken into consideration before cancelling the health club membership.
However, if it is just a good workout you want then push-ups and sit-ups are quite capable of getting you started. Then you can add other floor exercises for leg muscles, and then add further with back exercises.