A very simple but popular mixed drink on hot summer days is a mixture of equal parts beer and lemonade. It's called a Radler. It also only has about 2.5 % alcohol.
I did some googling and found something similar in Anglo-American countries, called shandy, often based on ginger ale instead of lemonade.
I also like Campari soda with ice as very practical, refreshing and simple, in contrast to sophisticated cocktails.
