Some more ideas

[artifact]

Primal Fungus
GG
Summon Fungus
Can't be the target of spells or effects.
If Primal Fungus does damage to an oppenent, it gains a +1/+1 counter.
1/1

Foreclosure
3UUUU
Sorcery
Gain control of all of target player's lands until end of turn.

Artifice Bane
2R
Enchantment
During your upkeep put a bane counter on Artifice Bane or pay 3 life to remove a counter.
During your mainphase, destroy all artifacts with mana cost equal to the number of bane counters on Artifce Bane.

How do you like these?

 

[Istanbul]

Foreclosure is pointless, mostly. You tap yourself out (probably) to get your opponent's mana. Then your opponent untaps on his turn...and you're still tapped out. It's only playable with some way to sacrifice your lands.

 

[Spiderman]

Primal Fungus reminds me of another card.. I thought it was Fungusaur but it's not... in any case, I think 1 colorless should be added.

In addition to what Isty said, if your opponent tapped his lands on his previous turn, they're going to come on your side tappd (the way it's currently worded).

 

[artifact]

The card it reminds you of is whirling dervish.

And as for foreclosure, not all the cards in magic are good. But sometimes ppl find awesome combos with crappy cards and turn them into a new deck style.
Don't know if you remember, but Channel at one time was consider the crappiest card in magic until someone got the bright idea of the first turn kill with it and earning that card a restriction and a banning.