BidHub was hastily built by HubSpot after finding out that this sort of thing doesn't already exist. Not for free, anyway.
So now it does. Give it a shot!
Keep up on items you've bid on, shine a light on underappreciated items with no bids, and search for words or specific donors.
Contact your winners after the event. Compulsively refresh during the event to see the current totals.
Know as soon as someone has bested your bid. Bid higher than your mental limit "because it's for charity".
Replace our graphics with yours and you could probably pretend you wrote it all yourself.