1. The most important thing is take time off of work when you can. I know it is hard if you are the one who is bringing home all of the income and you have a lots of responsibilities. If they are young take a half a day of work and spend the rest of the day with them. If they are older leave work earlier and pick them up from school or surprise them by being at home when they get home.
2. Take a vacation that is geared to your children. It is always fun to be a kid again no matter how old you are.
3. Always do something that your children love to do even if it something that you just don't want to do. They will enjoy it even more. If that means sitting watching the same movie for the 300th time and you can repeat each line word for word. Suck it up Dad.
4. If they are older go on school trips with them instead of Mom. Sometimes moms need a break if they are stay at home moms and spend most of the time with them.
5. Join a group,meetups or local dads that do things with the children as groups. This will allow you to talk to other dads and create new bonds with other dads and also have fun with your children.
6. When staying home with your children on bad weather days be creative. Do home made crafts. Create an indoor obstacle coarse. Even little kids like this.
7. Go to a museum especially the ones that are hands on. Children's Museums are perfect for that. Children love getting their parents involved.
Whatever you decide to do with your children when you are home. Enjoy them and love them. Cherish the moments because by the time you know it they will be adults.