Web: Just as you set out-of-office auto-replies for your email during holidays, it can be a good idea to do that on your favourite social networks too. Relaxed makes the process easy for Facebook and Twitter with a simple 3-step process.
Connect your accounts and Relaxed will prompt you to choose the dates you will be away for. There's no calendar plugin so you need to type them out in the given fields. Next, type out your message. You get up to 125 characters for your message because it's appended with "autorelaxed.com #relaxed" -- a bit annoying, but hey, it's free.
And that's it. Relaxed will send replies to anyone who writes on your Facebook wall or mentions you on Twitter. You have an option for it to also work with private messages on Facebook, but it doesn't work with Direct Mentions on Twitter. When you are back, turn off your accounts in the service.