Each year QRP ARCI organises an operating event known as 'The QRP Challenge'.
In 2013 the challenge is to work at least 100 QRP ARCI club members to qualify for The BIG 13 Award.
There was a time, in the 60s and 70s, when QRP ARCI members were working each other on QRP and exchanging membership numbers. In fact, some of the early issues of the QRP Quarterly were filled with reports from members showing achievements working other members – tracking their totals.
You may (in fact, are encouraged) to work members multiple times even though only the first contact in 2013 will count. Numbers exchanged during QRP ARCI contests will of course count toward your totals. You'll also be asked for the name of your favorite local, regional, or international QRP club (if you have one) and special recognition will go to those clubs who turn out the greatest number of members playing.
These are not Calling Frequencies, they are Centers Of Activity - places where QRPers are likely to be found.
Of course, you may operate QRP anywhere that your license allows. If you have a VFO, then use it - but check around the QRP Frequencies on a regular basis.