Reckless Prospecting
1R
Sorcery
As an additional cost to cast ~, discard a card.
Draw three cards, then discard a card.
Impromptu Abduction
2R
Sorcery
Gain control of target creature with converted mana cost less than or equal to the number of lands you control until end of turn. Untap that creature. It gains haste until end of turn.
Madness 0
Mineshaft Spellblast
5R
Instant
~ deals 5 damage to each player.
Dig 2 (2, Discard this card: Reveal cards from the top of your library until you reveal a land card. Put that card into your hand and the rest on the bottom of your library in a random order.)
Dwarven Desperado
1RR
Creature - Dwarf Rogue
When ~ enters the battlefield, duel an opponent. If you win, ~ gets haste until end of turn. (Each dueling player draws a card, then discards a card from his or her hand. A player wins if his or her card had a higher converted mana cost.)
3/2
Barbarous Outlaw
4R
Creature - Human Rogue
Madness R
Haste
When Barbarous Outlaw enters the battlefield, destroy target artifact. If its madness cost was paid, sacrifice it at end of turn.
3/3
Sandstorm Elemental
3R
Creature - Elemental
Whenever you cast a spell, ~ gets +3/+0 until end of turn.
2/4
There's a lot of debate to be had over Duel, but I believe the discard setup can be designed to make for a fun environment, despite previous assessment. Sandstorm Elemental, if it isn't obvious, is designed to play well with the potential to cast a normal spell and a madness spell in the same turn.