If you are feeling bored of always having to eat these amounts of meat when all your friends are doing barbecue.. why not have a look in the vegan/vegetarian kitchen for some variation?
(Besides.. if I eat meat more than twice a week I don’t feel well…)

On a swiss vegetarian page I found a great marinade among other tips for vegetarian barbecue:

For two persons blend the following together:

3 tablespoons dry red wine (or balsamico)
6 tablespoons olive oil (any high quality oil will do)
2 tablespoons of fresh lemon juice
1 tablespoon of mustard (strong (french) type)
1 tablespoon parsley, chopped fine

1 teaspoon oregano
1 teaspoon rosemary
1 teaspoon thyme

2 cloves of garlic, smashed

white pepper, ground freshly
salt (?)

then take eggplant, zucchini, peppers, onions, mushrooms, etc…
chop them in mouth-sized pieces and line them up on shashlik/kebap sticks.

spread the marinade over the sticks (is it really a “spit”?) and let it do its magic for a couple of hours, then wait till the meat-lovers have had their first fix (the marinade is not happy with too hot a barbecue) and gently grill the sticks.

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many other variations on marinades I found on the German “chefkoch” forum.

They also suggest that you could try to put chicken on the grill once.
Marinade is easy for chicken: Olive oil, salt, pepper, then add whatever you feel like eating. Here some suggestions:

– mediterranean
Rosemary, thyme, laurel, garlic, salt, pepper, olive oil

– hot
chillies, cumin, ground pepper, garlic, salt, pepper, olive oil

– with herbes de provence
– asian with lemongrass, soy sauce, ginger, honey
– try with tarragon once.. yum!
– oriental with saffron and cumin
– and, and, and…