。
I've got a great idea.
Literal
Great-idea [object-を] thought-up [masculine-ぞ].
名案 = 'great/brilliant idea' — 名 ('famous, notable') + 案 ('plan, proposal'). 思いつく ('to come up with, to hit on') is a compound of 思う + つく. The sentence-final ぞ is a strongly masculine assertion particle, used by men when announcing something with emphasis.