I have assembled here some of the material I prepared for various workshops I organised and for other teaching duties. Almost none of the material is original, most of it comes from various books and some riddles are folklore, I guess. Some notes are only in German but if you are interested in running such a workshop and want some ideas and if your German is not good enough, just contact me and I will translate them. Also, if you know good sources of similar suitable material, please tell me about it. The following stuff was intended for 8-10 year olds (all of it as word documents): I have got a lot more in the same vein so just ask me. The following material was prepared for a workshop for 15 to 16 year olds. Unfortunately, I haven't translated it into English yet. It's all in pdf format: Finally, here is a document about semi-direct products of finite groups which my and other peoples' Galois theory students from Cambridge have usually found useful.