Family-Focused
Consider creating a board game with your family life as the focus---and teach kids a variety of skills and values. For example, reinforce positive behaviors with bonus squares for things like "Share your toys and move ahead three spaces" or "Clean your room and move up one square." Alternatively, you can have penalties for other things, but try to keep them light-hearted and funny like "Poured chocolate syrup on the cat, move back one space."
Alternatively, you can make it interactive with the rest of your life. For instance, don't leave specific numbers on moving forward or back spaces---if the bonus square says, "Share your toys," ask the player how many times she has shared that day and that's how many spaces she getsto move forward. Or if the square says, "Left clothes/towels on the floor," go on a hunt and see how many things that player has left lying around, and that's the number of spaces he has to go back (plus, the stuff gets picked up at the same time!).
Learning Games
Additionally, you can make homemade kids' board games focused on learning specific things, such as colors, letters, numbers, phonics or even a specific topic such as dinosaurs, trees, animals, rocks, math, geography or history. Create flashcards with a picture or question on one side and the answer on the other. Players draw cards out of a box and read it to the player whose turn it is. The player whose turn it is has to correctly identify the picture or answer the question to move forward.
You can also make bonus cards where the player gets extra spaces for answering harder questions, or list cards where they get to go as many spaces as they can---like "List words that rhyme with 'BOOK'" or "Name varieties of flowers."
Other Considerations
Homemade kids' board games can also just be fun and silly, with no learning agendas---although it is important to make sure the game isn't sending hidden messages condoning violence, cheating or dishonesty, etc.
Additionally, you can modify store-bought games you already have by creating new pieces or rules, or by using a plain board for a completely different game. For example, if you have a chess or checker board and have lost the pieces, make your own pieces---use pictures of your family as chess pieces or cut out magazine pictures of dogs for red checkers and cats for black checkers.