Special Pop-Up Help

[shoppingtelly]

Hi there,

Bit of a complex thing, but here's hoping someone will know...

Is there a way of creating a pop-up page that comes up every time anyone comes onto our forum, so the main index.php page. But only comes up the once, so once they dismiss it, it stays off for that session.

But also we need it to only pop-up for an hour between probably 10pm and 11pm, so anyone who visits the forum then gets the pop-up page which would be a website with a multimedia player on it.

Would be really grateful of any help.