I think Alty could put together a pretty good offer, built around attracting people to a high profile and a low profile game.
Something along the lines of a 'friends of Alty' promotion designed to get people to bring more people along. It'd need proper support and marketing though.
I'd work it around the fixture list where we've got an attractive match followed by a less attractive one and make an offer built around the two to bump up attendances for both games rather than just one. I'd also aim it that way so that any 'loss' is mitigated against the additional full price sales.
IE - everyone attending the (theoretically) decent game pays full price but gets the opportunity to take up the offer for the next game, be it a buy one get one free offer, or 2 tickets for £10 to really give it a go.
It could be abused by a few people, but on the whole the discount would be built around rewarding loyalty rather than just a cheap offer accross the board. By the same token, I can't see season ticket holders feeling they've missed outtoo much; they may feel they're losing out on a couple of quid but sure they'd see it for the greater good.
It'd need decent internal co-ordination and it should be done to also gather contact info (email addresses, or through something such as facebook) for future marketing purposes.
I'd explain it better but I'm tired; sure you can get the gist.