What do I plan for at an engagement party?

My fiance and I have just recently got engaged and have started planning for a party. We have a venue sorted and the guest list but I'm still unsure as to what to do at it. We don't have a lot of money and we aren't planning on catering as it's to expensive. What sort of things can we put on at it? I know it is not tradition for the couple to host but we don't think that's too important nowadays. Any help will be appreciated.
We aren't planning to have the wedding till late next year or the year after, so we do have time to save for that. We have enough money just not thousands of pounds to use on a party. we are very social people so having a party is a must for us and of course it's all in line up to the big day!