Exercise in some way 3x a week for 30 minutes and keep my heart rate in my target zone while doing it

I spent over an hour jumping on my sister’s trampoline with both my neices, 4 and 9! If that wasn’t a good workout I dunno what is!

I have a video and its 45 minutes long. Almost the entire time my heart rate is in my target zone. I’d like to continue on with this but it gets kind of boring after a bit so I’d like to do other things. Maybe get a membership to the Y so I can use a treadmill.