1. Get a friend to send you a Free Gift. Preferably a 'Light Snack'
2. Go to Games (see image above)
3. Click Accept and Play
4. You should see that the item is accepted. Copy the url which should look something like this '
[You must be registered and logged in to see this link.]
5. Notice the &gift=meal1 (may not be meal1 if you did not receive a light snack)
6. Change meal1 to picnic_basket or any of the items below. But i believe picnic_basket has no limit and you can get like hundreds of it. Other items seems to work only once.
7. With the picnic_basket url, you can just keep refreshing and get lots of it.

Other item IDs:
meal1
meal2
meal3
meal4
picnic_basket

hand_drill
hammer
paint_bucket
bricks
nails

spitball
ink
pen
chalk
slate
ribbon

ox
cow
sheep
goat
chicken
goose
pig

cherryfront
pinefront
applefront
peachfront
apricotfront

hay
bucket
gift_mystery1
gift_mystery2
gift_mystery3
gift_mystery4
smallflowers_blue
smallflowers_yellow
opencrate
cobblestone_border