Hearthpwn

So this deck was made purely for fun, yet it amazes me how much ruin it leaves behind and how good the combos are.
The best hand to begin with is an Undertaker with any deathrattle minions that fit the curve after it. That is the perfect start. Once you have a favorable set of deathrattle minions on the field try to get the Baron Rivendare on and from there to Stalagg and Feugen being ideally eaten by Void Terror to get 4 Thaddius on the field.
Of course this is an ideal scenario, but let me explain the pros and cons of these and other cards:

Stalagg and Feugen:
Great 5 drops that can work well with other Feugens and Stalaggs from you opponent.

Void Terror:
Eats anything from Nerubian Egg to Stalagg and Feugen or any card too many on your field. Great with Kel'Thuzad as it brings back full health minions anyway.

Kel'Thuzad:
Just owns the board once you deathrattle a ton or just have board control. Great with Thaddiuses and can even combo up more Stalaggs and Feugens. All in all just a crazy card to have here. But beware which minions you kill first as it will kill some if you have a full board.

Soulfire:
Great finisher, but not so great if it discards your Stalagg Feugen combo, so try to use it or get it towards the end.

There are a few cards that can be replaced with ease such as:
Summoning Portal: It is not a mana-demanding deck, so it can just speed up the combos, but it is not crucial. Replacement: Any deathrattle minion.
Sunfury Protector: Works with Nerubian Egg, works with getting your beef minions taunted, yet overall very situational. Replacement: Ant deathrattle minion or Defender of Argus.
Coldlight Oracle: Usually useful but sometimes inusable if you have control while it becomes a low-on-cards game. Replacement: Any deathrattle minion or any Draw card.
Azure Drake: Good overall card, it draws and it buffs some useful spells. Replacement: Bloodmage Thalnos

Anyhow, this is a cheap deck with a lot of fun.