Symphonic prayer: This is when all the people in the church pray out loud at the same time. Just as a symphony has differing instruments that play a harmonic melody at the same time, this is the way Pentecostals will pray out loud, together, yet in harmony. Of course, there are many times that prayer is lead while the church prays silently.
Lively praise and worship service: You may see people raising their hands (a sign of submission to Gods will), lifting their voice in praise, leaping (like someone who has received a great gift would leap for joy), dancing (an outward expression of the happiness they feel inside) and hand clapping, and yes laughing. To name just a few. It is usually (but not limited to) this time that people in the service will speak in other tongues. This is what the Bible teaches us as a "prayer language" that the Lord gives to all who ask Him. Though these expressions of praise, worship, and the Gifts of the Holy Spirit may seem different to those who are unfamiliar.