1. Intel-Altera: http://www.bloomberg.com/news/articles/2015-06-01/intel-buys...
2. Avago-Broadcom (and earlier, Avago + LSI): http://www.bloomberg.com/news/articles/2015-05-27/avago-said...
3. Silicon Imaging-Lattice: http://www.wsj.com/articles/lattice-to-buy-silicon-image-for...
4. NXP-Freescale: http://www.eetimes.com/document.asp?doc_id=1327236
5. (2014) Cirrus-Wolfson: http://www.eetimes.com/document.asp?doc_id=1322171
6. Avago is further looking at Xilinx, Maxim, and Renesas: http://www.reuters.com/article/2015/05/14/us-chipmakers-m-a-...
This is one industry that is in flux ATM.
Edit: Further afield, though tightly coupled with this industry, on the manufacturing equipment side, Lam Research announced acquisition of KLA-Tencor today http://www.wsj.com/articles/semiconductor-firm-lam-research-...