This has been implemented by the third party SMS Auto Respond Plug-in, which is available on the Android Market. https://market.android.com/details?id=com.suttco.locale.telephony.sms

Good news!

Android 4.0 finally grants apps official access the built-in calendar, so we’re planning to support this with a new Calendar condition. This new Calendar condition will be Android 4.0+ only.

As a general design principle, Locale only has features that Android officially supports (for the developers out there, we only use public APIs). This ensures that Locale works reliably across different versions of Android and different Android devices. For those without Android 4.0 (or those looking to live on the edge), there are some third-party plug-ins that implement Calendar condition functionality. These plug-ins are using undocumented Android APIs, and may therefore not work on all devices or may break when new versions of Android are released. Anyway, here are links to these plug-ins on the Android Market:

https://market.android.com/details?id=org.acm.steidinger.calendar.localePlugin

https://market.android.com/details?id=com.DroidMunkey.LocaleCalendarConditions

Locale is exclusively available through the Android Market, and can be found here: https://market.android.com/details?id=com.twofortyfouram.locale

We did sell Locale via our own website between mid-2010 and early-2011, in order to support users without access to the Android Market. Since then, the Android Market has become available in many more countries so it is no longer necessary for us to sell Locale directly through our website.