I sometimes have the desire to do spontaneous things more days than others, and they'd usually range from little things to smaller things. Littlest being to just falling onto my bed for no reason to a big thing such as dancing in the middle of an isle in a grocery store. Once, as a kid I just dropped to the floor of the mall spontaneously in protest of wanting to go back home because I was tired and hated shopping back then.
If I follow through with them depends solely on how badly the urge is and how daring I may feel depending on how big of a spontaneous action it may be. Overall, I like to keep things spontaneous, because it keeps life interesting.