(Sorry for the long title.) With over 4,000 cards, Forge has a heaping-load of card slapping fun. (Hey, I remember when Forge had only 1,200 cards and I could practically name all of them.) Since Forge is soooo big, there are many features/cards that you may not be aware of.
You can change the basic land card pictures. For each land Forge looks for 4 files: forest.jpg, forest1.jpg, forest2.jpg, forest3.jpg. So you can change these files to whatever land strikes your fancy. The full frame Zendikar lands are beautiful and you can download them here. Put them in your /res/pics/ directory.
There are a number of unusual keywords that I didn't know Forge had like suspend. Suspend lets you pay less now and then the card resolves later after a few turns. Durkwood Baloth (Creature, 5/5) is a good example. You can cast it for 4GG or using suspend, pay G and then wait 5 turns until it resolves. Forge has 18 suspend cards, you can find them using the Filter menu in the Deck Editor. (Leave the "name" field blank and in the "card text" field type "suspend".)
If you are tired of seeing the same cards during a draft or quest, download this file. To change the draft, extract it into your /res/draft directory. To change your quest, extract it in into your /res/quest directory. These files are "flat" and have no rarity, all cards have an equal chance of appearing.
I absolutely love the "Generate Deck" option. You can remove creatures with 1 or 0 power or artifacts by using the menu. In the New Game screen, click on "Options" then look in the "Generate Deck" submenu. I have had some fabulous games. One time I actually used Fastbond to win and Fastbond is a pretty bad card. (Fastboand - G, Enchantment - You may play as many lands as you choose on your turn. Whenever you play a land other than the first land of the turn). I just happen to get a bunch of lands and a 3/3 creature, so I took the some damage and played my 3/3 on turn 2, boo-ya!
If you want a change of pace you can download a new mana pool picture here, put it in your /res/pics/ directory. It features all five Unhinged basic lands.
If you have other questions about Forge, feel free to post it to the forum.