Simple Scoring Board is my project for Digital System Theory class, last semester. I didn't do it alone, but I did it with my friend. Basically, it's a counter circuit. It can show you the scores for both teams which doing the game, from 00-99, it uses 4 seven segments, 2 seven segments for each team. Also it uses up counter IC CD4026BE, 3 switch buttons, 1 ON/OFF switch, 1 LED as indicator, 9V battery and anti-bouncing circuit. Here is how it looks:

This is the original schematic of simple scoring board:

Then, I put anti-bouncing circuit on the up counter switch button, because the number that shows on seven segment didn't came up in line. This is the anti-bouncing schematic circuit:

This is the logic diagram image from CD4026BE datasheet:

This is how it works:

As you can see from the logic diagram image, CD4026BE clock pin is active high, it means the IC will start counting whenever the clock pin in HIGH/1 logic condition, to prevent the IC for counting I must connect it to ground, so the clock pin will be in LOW/0 logic condition. To show the number that counted by the IC, I connected the seven segment output pin(6,7,9,10,11,12 and 13) to seven segment. Dont forget to conncet pin 3(display enable) to Vcc(power source). To reset the counter, I connect pin 15(reset pin) to ground, that is why I put pull down resistor on reset switch button.

See also this project on my blog: http://adventureartengineering.blogspot.com/2013/05/finished-simple-scoring-board.html