So what is baptism in the Holy Spirit?

Anyway, all I want to do today is suggest an answer to the question. It's tentative (in that I want to further nuance and refine it), and requires a bit of unpacking (which I shall do in the near future — perhaps next week). But here it is for your consideration:
The Baptism in the Holy Spirit is a gracious and powerful encounter with the Triune God in which Jesus pours out the Father's promise of the Holy Spirit to fill believers and equip them, as members of His Body, for mission and service in His power.
So what do you think? Let me know in the comments.
And if you want to read a bit more about the baptism in the Spirit in the meantime, here are some older posts about what it's for, when it happens and it's relationship to the Cross.