Frugal ways to have fun in the summer (and all year round actually)

I answered a question on Reddit about this that got me thinking about cheap ideas for some fun, here's what I've got so far:

• Go and visit an animal shelter/petting zoo, or a zoo/aquarium if there is free entry, this is great as a family or a couple just to spend time with eachother and look at the cute things. 
• Bowling alleys with deals, the ones local to me have things like £5 unlimited play all night on some weekdays, it isn't THAT cheap but not bad I think for hours of entertainment (don't buy drinks), may be more expensive in the US.
• Cook something cool together, make a picnic then go and enjoy it somewhere nice, or try some creative themed recipes, or make some delicious dessert and try not to eat it all the same day.
• Visit local markets (farmers market, seasonal things, food fairs with free entry), there can be some cheap trinkets otherwise the experience is always nice, make sure you have eaten beforehand as some of these things smell divine.
• Get a free ebook reader, the Kindle Reading App will let you read on most PCs, smartphones and tablets. If anyone in the UK wants a kindle for your kids you can get one with 2 year accident protection, the latest Kindle and a kid friendly cover.
• You can grab a Kindle Unlimited 30 day free trial at the same time as you get the ebook reader, this gives unlimited reading of over 1 million ebooks and listening to thousands of audiobooks. I recommend you only join one trial at a time, unless you will be using them concurrently, as this way you get entertainment for several months rather than using it all up instantly.
• Join prime instant video for a free trial and watch unlimited movies and TV shows, with this you also get access to prime music (ad free music streaming). UK link, for fellow brits you can get just Prime Video for £5.99 a month (cheaper than Netflix)
• Google free museums/art galleries in your own
• Look up project ideas/cheap arts and crafts, you could make a kite and go fly it, pick up a DIY project to improve your home/a bit of your furniture so you're saving on new items/making it look better. 
• Go hiking, or camping if you've got/can get the stuff for it. (Borrow from friends/family?)
• Make some money - isn't that the most fun someone could have?! Although it isn't lucrative at all for me, running this blog I feel like I learn things and it doesn't cost me anything - just my time/electricity (and I suppose paying for internet), if you can make money from your passion its a win-win. Check my guide to passive income, or some other information about saving money.
• You can get a free trial of showtime or SEESO as well, you don't need to have a cable subscription.
• Do a jigsaw, in the UK you can pick them up in charity shops for like £2 for 1500 pieces, I got conquered by one that was half black.
• Start running, this one is fun for your body (haha I'm just kidding) and your mind. Check out parkruns for a free run that has timings so you can set goals/feel more motivated.
• Hit up the library, or sit in a bookstore for a day and read. If you like Audiobooks try a Audible US trial for two free audiobooks that you can keep after you cancel the trial (cancel it after getting your chosen audiobook so you aren't charged), Audible UK
• Put on loads of sun lotion take a drink and a snack, go somewhere nice and get some vitamin D.
• Host a jacob's join/pot luck - this is fairly inexpensive and you get to enjoy a meal with your friends and loved ones, and eat lots of delicious food! 
• Join a sports club/team, you can pay each time you play or subscribe for a year, this works out cheap compared to other activities you can do and it is a great way to meet people.
• Go on a frugal holiday, see top ways to have an amazing holiday for less or grab a bespoke holiday itinerary from me, first person to quote "dizzy skunk" to me can have a weekend planned for $3. This isn't all that cheap but I went to Athens for a week for under £500 (two people including flights, hotel, eating out whenever, 1 day in London + hotel in london, trains), so if you have a little more saved up you can have a lot of fun!