Visiting Colorado Springs (snowy there today!) and went to the ANA Money Museum. It's quite a place and worth the trip if you're ever in the area. It's naturally heavy in modern US coinage, including a spectacular collection of gold coins and pattern pieces. However, they do have an exhibit on the history of money. Here's their Roman coin display. I apologize for the quality of the photos; it was hard to photograph them through the glass and no flash photography is allowed (which would have made things worse anyway).
And just a few blocks to the East, you could have hit Ken Hallenbeck's coin shop. That's where I bought these two guys years ago which helped me down this path (I miss that town...) Imperial Rome Caracalla, r. 198-217 A.D. (205 A.D.) Rome Mint, AR Denarius, 19.17mm x 3.3. grams Obv.: ANTONINVS PIVS AVG, Laureate bust right, draped Rev.: LIBERALITAS AVGG V, Liberalitus standing left, holding abacus and cornucopia Ref.: RIC IV-1, 136b, p 232. R2 Imperial Rome Caracalla, r. 198-217 A.D. (211 A.D.) Rome Mint, AR Denarius, 20.28mm x 2.8 grams Obv.: ANTONINVS PIVS AVG BRIT. Laureate bust, right Rev.: P M TR P XIIII COS III P P. Pax, draped, advancing left, holding branch in right hand and sceptre in left hand Ref.: RIC IV-1 Caracalla 184, p. 238. C Hope you had a fun trip!