Lánzate

Una lanza is a spear. The verb lanzar, launch, appears in a few useful expressions.

Lánzate

Informally, lanzarse works for head out somewhere, especially without delay.

• Lánzate de volada antes de que cierre la tienda. Go now or the store will be closed by the time you get there.
• Saliendo del trabajo me lanzo para allá. As soon as I get off work, I'll head straight there.

With para, lanzarse works for candidacies: Se lanzó para alcalde. He ran for mayor.

Se me lanzó

Lanzarse is also used for the idea of declaring romantic interest. Se me lanzó. He let me know he's interested, literally, threw himself at me. Lanzado means forward, aggressive. Anda súper lanzado. He is hitting on me, coming on strong.

Pasarse de lanza

Pasarse de lanza means: go too far, be out of line, exceed acceptable boundaries.

• Te estás pasando de lanza. You're really out of line, asking for it, risking more than you should, taking advantage of a situation.
• Ya se pasó de lanza. She really screwed up this time.

Also heard is pasarse de la raya, literally, cross the line.