Yesterday, the IDF went into Gaza in force for the first time since the "calm" in order to destroy the opening of a tunnel that was meant for abducting Israeli soldiers. As a result, six Hamas members were killed, and chances are that the streak of 19 weeks in a row of more internal PalArab deaths than IDF-caused deaths is going to be over this week.
While the IDF took pains to say that this was a one-time only operation to defuse a "ticking tunnel," and clearly building tunnels to kidnap soldiers is also a violation of the truce, Hamas has responded with 35 Qassams and mortar shells. And Hamas took credit as well, claiming 33 mortars and 4 rockets.
UPDATE: By sheer coincidence, Hamas' Qassam Brigades' leader said on Monday "we vow to strike the Zionist enemy anywhere inside the occupied Palestinian territories, therefore we will, Inshallah (God's Willing), carry out quality operations inside [Israel]."