Guinea pigs please help~?!?!?!?!?!?!~?

hi i have had my guinea pigs for about a week now male and female we are going to have one litter to keep i have already been to the vet who will charge me 20$ to get my female spayed after one litter. BUT anyway i really want to know some toys i can make for them i have plenty of timber nails boxes branches all i need is to know some ways to make them really fun toys they already have a big green rabbit igloo i just want to know what else i could MAKE for them