We've got a lemon tree and an overabundance of lemons at the moment. Aside from lemonade, what should I do with them? 
Well there are a myriad of nice lemon recipes of course.  A decent lemon drizzle cake usually goes down well.  However, if you really have a glut, consider making a batch or two of lemon curd, or even preserving/pickling them like the North Africans do. 