 The Cboe Volatility Index and VIX-related exchange traded funds were in full swing as fear and uncertainty fueled wild market swings this week. Among the best-performing non-leveraged ETFs of Friday, the iPath Series B SP 500 VIX Short Term Futures ETN NYSEArca: VXX increased 10.5 and the ProShares VIX Short-Term Futures ETF NYSEArca: VIXY advanced 10.4. 