Thank you so much feeb and ubba82 for your suggestions, they were GREAT!

I went to the shops today and I got the boy a footy - $25 (please tell your DH ubba82 and thank him for me) and the girl a skipping rope - $5. I am really happy with these gift choices because it is the boy's birthday, so he should get the bigger more expensive present, but I didn't wan the girl to miss out. And they are both active outside things that will hopefully be useful and last. And I came in exactly on budget! WooHoo!

Thanks again girls!