Election night is a big traffic boost for news and social sites. Yahoo expects up to 400 million page views on Election Day. Data Center Knowledge has an excellent article how various sites are preparing to handle spikes in election night traffic. Some interesting bits:

Prepare ahead. Don't wait to handle spikes, plan and prepare before the blessed event.

Use a CDN. Daily Kos puts images on a CDN, but the dynamic nature of their site means the can't use CDN for their other content.

Scale up. Daily Kos "to handle the traffic better, we moved to a cluster of six quad core Xeons with 8GB RAM for webheads that all boot off a central NFS (Network File System) root, with the capability of adding more webheads as needed,” . They also "added two 16GB eight-core Xeons and a 6×73GB RAID-10 array for database files running a MySQL master/slave setup."

Add Cache. Daily Kos added 1GB instances memcached to each webhead.

Change Caching Strategy. Daily Kos puts fully rendered pages into memcached.

Change Serving Strategy. Daily Kos directly serves cached pages from memcached directly to anonymous users from lighttpd running as the front end proxy. The moves a lot of work off the backend and distributes work on the new hefty webheads. Site performance has improved greatly.

Add Capacity. Limelight expanded its network capacity to over 2 Terabytes per second. Tonight is a big night for a lot of sites. It's interesting to see how some are responding to the challenge. A lot of what they are doing will work for you too.