The Gizah pyramids are not the only ones near Cairo: there are more than 80! the most famous of the other ones are in Saqqara (the Zoser pyramid) and in Abu Sir.
Most probably you won't have time to visit the pyramids in Abu Sir, but you should spare some time to visit the one in Saqqara. To get there you can take a taxi or ride a horse or a camel (the horse/camel ride can take more than 5 hours, though).