Duel Portal is a program where you can create Yugioh cards and duel with them, you can even use other users cards with them sharing their cards with you.
First what you need is silverlight, u can download it here
- Spoiler:
Then after that, restart your computer and then open your browser, type in :
duelportal.tk then register, confirm your email and you are set.
If you ever made a card using a yugioh card maker or yugico card maker and wanted to try it
this is the place. You can even use real konami cards and the whole deck.
If this does not work try updating browser and then trying again . GL