I think this is something Stef should have a list of, but in case he doesn't it's pretty standard. A list of things that are simple to implement, require a minimum of testing and resources. A good rule of thumb is 12 hours tops, no more than $250 in external resources (so don't suggest animated cards or an iphone app), nothing complicated (so no getting buttons out of chat, that clearly requires more than a few lines of code being tweaked).
1. Initial splash screen with information about what Dominion is.
2. Link to Rio Grande setup (https://www.youtube.com/watch?v=WxPd1GymxSU
) and Rio Grande live play (https://www.youtube.com/watch?v=b15pTChFg9c
) for new player instructions.
3. Prepare a new player video similar to the above for the client (stretching the criteria, but you can probably pay for one for $250ish)
4. Pricing on main page. Include that it's free to play for anyone and free to play with any expansions your friends have.
5. "Games of the day" with random game logs between high level players featured (maybe expanding to a full blown 'watch them play in client' someday, but outside this scope).
6. Show attacks that are out on opponent's side of the field (even just card name). Information currently in mouseover box, so displaying it differently, even if ugly, should not be a hard implement. Push off dynamic implementation (markers that appear when an attack is active, but don't if it's blocked by something like moat/lighthouse), just get the static info we currently have in a noticeable spot.