Hindi theater has close association with Bollywood, many of the best comedy skits available are influenced by it and include it in parts. Bollywood in turn has been making movies in lines of Hollywood, Tamil, Malayalam and Telugu movies. So we can get all these as subjects in most Hindi plays that are played in theaters. Here is a link where you can get good comedy skits in Hindi:
Bollywood movies are the best choice to extract ideas for Hindi comedy skits. Beauty and fashion also contribute to the lot. The most fascinating ones will be game shows and talk shows. All you have to do is observe their body language, make over and attitude and create a comical skit for example “Kaun Banega Mera pathi?” The link contains more information on ideas and themes for Hindi comedy Skits.