I love hearing about other people's plans & maybe grabbing some inspiration, so here goes 
My plans, with DSes aged 10, 7 & turning 5 on Wednesday (and DH for some of it) & little money are:
Swimming in normal pool on Sunday with DS2 & 3 while DH & DS1 are at football (free with their lessons + me being carer for DS2, who has ASC)
Swimming in different pool with slide & waterfalls another day for DS3's birthday (his request)
Eat out on DS3's birthday (either Pizza Express/Prezzo with vouchers or Toby Carvery breakfast with kids eat for £1)
One day my parents are taking DS1 go-karting with his cousin as his late birthday present, so we'll all watch. Then I am working that afternoon (new job, love it, wish it paid more!)
Possibly seaside one day (take wellies & picnic to eat in car while looking out to sea)
Possibly country park of some sort on another day, with friends if DH is working that day. We have a few nice trails around here - Stick Man, Gruffalo, Wind in the Willows, Peter Rabbit, Zog.
I feel happy just thinking about it all 