Filming cocktail hour
 

Is there any way to make cocktail hour interesting?

nothing I've ever found. :-(

However I usually get about 15 minutes of that unless there's a receiving line then add about 10 minutes. Once I've got that I try some "fancy" stuff. Snap zooms, swish pans booming with those things if possible, anything to keep from falling asleep. After about 30 minutes of roaming around and people waving at the camera OR turning away from it I usually put it down and take a few minutes to refresh myself.
I really don't use much of the footage anyway but like I always say "you can't edit what you don't have".

What's cocktail hour?

In most of the US after the ceremony before the reception actually starts there is a time (generally about an hour) where the B&G and guest get to greet one another, have a drink an o'duevr (sp) and relax a bit before the festivities of the receptiob kick off. In many cases the photog will take some formal shots of the B&G at a background and many will have a recieving line where they line up and shake hands and trade hugs with the guests.
Nothing exciting happens at this time (usually).

We usually start off with a few establishing shots of the location and then move into some wide shots of people "mingling". If there is passed food, we usually stand still and pivot as they pass us by. If there is an actual bar, I like to shoot down the bar as drinks are being passed from the bartender to the guests. Another cool shot is to place the camera on the bar, zoom all the way in and do a slow zoom out. You can also do some cool focusing things with the different drinks. From there you really can only get decorations and people talking/laughing. Try to get as many different angles of the event as possible. An hour long cocktail hour usually ends up being 10-15 minutes on the DVD.
HTH!

During that moment, I would try to film the catering/in the kitchen. It's about to get pretty busy there, with all the hors d'oeuvres (appetizers) and first courses waiting to be prepared.
Maybe you can make ultra close-ups of small elements, which you can later re-use for say a DVD-menu background.
You could also interview people.