Is this a [[milkround]] event - at your uni? The business game will be something lihe a [[group exercise]] I imagine, but less taxing. The opportunity to speak to people means that there’ll be two or three HR people and some graduate trainees from E&Y available for you to ask questions about their jobs and the firm, etc.
You want to make a good impression and try to get people’s emails/contact details if you can because these can be useful if you have questions in the future. This is really an opportunity for you to find out about the firm though, more than an assessment of you… at least I would have thought so.
Dress smart - a suit if you want, a shirt and smart trousers would probably be ok.
Mention the fact you use WikiJob and ask them what their thoughts are on modern recruitment tools and user generated recruitment media such as WikiJob. That’s a good question!