brainwanderings

I just came back from a month-long trip overseas and realized I had no other plans for this summer. I'm missing life in the lab and am thinking of either contacting the PI I had last summer and asking if his lab needs any help with their current projects or contacting my new MSc PI and asking if I can begin my graduate project early. I realize it's June so it's probably too late to start any real independent research work before my MSc. I wanted some advice on which option would be best/most likely. Thanks!