Perhaps it is possible to create an instant global (or national) warning network, in case of pending doom (think tsunami). Messages would initiate from a trusted source and would propogate much like an email virus but with source authentication at each transfer. A client program would monitor a designated socket with low duty cycle, when a warning is first received and authenticated, it would log the receipt and propogate the message forward. Subsequent receipts of the same warning would be ignored.
If OLPC is successful, then this platform could be used to support this warning network.