1)Firstly, i'm living in Russia and we aren't so much different from foreigners, at weekends we are preparing for next week, have a rest, and do staff that we can't do while week.
2)Well.. i guess, the best season is summer, because the weather is nice, you can walk with your friends or gf, also you have an opportunity to play some outdoor games like:football, volleyball, basketball and etc.Yo don't need to wear warm clothes,its enough to wear short and T-shirt.
3)I usually spend my weekends with my friends for a number of reasons.Firstly, we are doing same activities, we are like-minded people, and its literally fun with them.Secondly, they don't asking silly questions like family members do.And thirdly, ther are my friends and its pleasure to spend time with your friends.