Have any of you ever been filled with the Spirit?
Yes. We are commanded to be filled with the Spirit. We do this by inviting the Spirit to work in us as we obey the commands of Jesus.
Initially, we know it by faith, but then we see that the Spirit is giving us grace to keep the commands of Jesus and move away from the sinful habits that entangle us. We see actual changes in our lifestyles and attitudes.
I wouldn't say there is any particular feeling to being filled with the Spirit. However, I think you are actually referring to being empowered by the Spirit in ministry - where the Spirit endows you with power and giftedness for a certain situation/moment. Those times I often "feel" confident, joyful and filled with wonder because I know that God is about to do something in our midst - even if it is going to be a word of correction. This is usually associated with a well-known spiritual gift in one of Paul's lists, but not always.
Were there any outward manifestations of it?
Often there is a sense of God's holiness in the room - something of a spiritual heaviness or majesty - where everything is laid bare in an emotional sense. I don't mean that everyone is crying - not at all - but that honesty is required. If one cannot be honest, then one knows they should not dare speak.
Was this filling connected to any event (revival, church service, etc)?
The filling of the Spirit should be an everyday thing. The manifest power of the Spirit using you and the gifts you have been given may not happen every day but happens in connection with ministry to others - whether one on one or in corporate settings of worship and ministry.
I have most often experienced the manifest holy presence of God in corporate worship - once for a few minutes at a chapel service at Southwestern Seminary in 1995, at a small worship service at a church men's retreat in 2005, and probably half a dozen times at my home church during a period of true revival (not a series of intense meetings, but over the course of nearly 24 months where we saw God have mercy on our congregation and glorify Himself among us).
All that being said, I don't think we should seek an experience or feeling or use that as a qualifier as to whether or not the Spirit is working. When Jesus was on the mountaintop and was transfigured before the three disciples, Peter offered to build shelters for Jesus, Moses and Elijah so they would never have to leave. That obviously was not God's plan. I think we need to appreciate and cherish those times when God pulls back the curtain and we understand that we are in the presence of God (as we are all the time anyway), but He hides Himself to an extent so that He does not overwhelm us with His majesty so that we can become the kind of people He is calling us to be by obeying the commands of Jesus, serving others, and making disciples.
Now, this: I am a soloist. Sometimes, when I am singing, I become aware that I am singing better than I'm capable of doing. I'm hitting notes that are normally a stretch; the hearers respond with tears, with various responses ("Amen, Hallelujah"), sometimes raised hands, sometimes applause. Sometimes it happens when the choir sings.
My own reaction is "wow, the Holy Spirit is moving in this place."
Sounds like the Spirit is using you to bring glory to God and bless His people.
Is this merely emotion brought on by music, or can this be a real pouring out of His Spirit?
Music is such a powerful thing and can draw up all kinds of emotions. I would venture that God is using you and the Spirit is truly working among His people there, but I wouldn't necessarily use the phrase "pouring out of His Spirit." In the New Testament, the pouring of the of the Spirit seems to be used for life-changing turning points in the church.
And something else to think about: people tend to confuse emotions and emotionalism with the work of the Spirit. Since emotions are a God-given part of who we are, it is natural that there will be emotional effects when the Spirit deals with us. But a truer barometer of the Spirit at work is repentance and faith - not just conversion, but a realigning of our lives to live more obediently to the commands of Jesus.
One of the tragedies of the Christian life is that when someone has a profound spiritual experience, instead of benefitting from it and moving forward, all to often the focus turns into seeking a repetition of that experience. Jesus had this trouble with the crowds seeking after him to see healings or get miraculously feed instead of focusing on His teaching. In my opinion, that's one of the main reasons we don't see many public miracles today. Instead of people having faith in Jesus and following His commands, too many people (me included) would easily get distracted by the miracles.
And from the accounts in Scripture they didn't ask for it either, He empowered them as He saw fit. I guess we can ask for it, but like any petition to God it is not guaranteed.